Objective To verify the regulation of acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT 2), which is associated with cholesterol metabolism, by saturated fatty acids (SFAs). Methods Palmitic acid (PA), the most abun...Objective To verify the regulation of acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT 2), which is associated with cholesterol metabolism, by saturated fatty acids (SFAs). Methods Palmitic acid (PA), the most abundant saturated fatty acid in plasma, and oleic acid (OA), a widely distributed unsaturated fatty acid, were used to treat hepatic cells HepG2, HuH7, and mouse primary hepatocytes. In addition, PA at different concentrations and PA treatment at different durations were applied in HepG2 cells. In in vivo experiment, three-month male C57/BL6 mice were fed with control diet and SFA diet containing hydrogenated coconut oil rich of SFAs. The mRNA level of ACAT2 in those hepatic cells and the mouse livers was detected with real-time polymerase chain reaction (PCR). Results In the three types of hepatic cells treated with PA, that SFA induced significant increase of ACAT2 expression (P<0.01), whereas treatment with OA showed no significant effect. That effect of PA was noticed gradually rising along with the increase of PA concentration and the extension of PA treatment duration (both P<0.05). SFA diet feeding in mice resulted in a short-term and transient increase of ACAT2 expression in vivo, with a peak level appearing in the mice fed with SFA diet for two days (P<0.05). Conclusion SFA may regulate ACAT2 expression in human and mouse hepatic cells and in mouse livers.展开更多
AIM To examine the changes of the ghrelin/ghrelin O-acyltransferase(GOAT) axis and the mammalian target of rapamycin(m TOR) pathway in the hypothalamus after sleeve gastrectomy.METHODS A total of 30 obese type-2 diabe...AIM To examine the changes of the ghrelin/ghrelin O-acyltransferase(GOAT) axis and the mammalian target of rapamycin(m TOR) pathway in the hypothalamus after sleeve gastrectomy.METHODS A total of 30 obese type-2 diabetes Sprague-Dawley(SD) rats, 6 wk of age, fed with high-sugar and highfat fodder for 2 mo plus intraperitoneal injection of streptozotocin were randomly divided into three groups: non-operation group(S0 group, n = 10), sham operation group(Sh group, n = 10) and sleeve gastrectomy group(SG group, n = 10). Data of body mass, food intake, oral glucose tolerance test(OGTT), acylated ghrelin(AG) and total ghrelin(TG) were collected and measured at the first day(when the rats were 6 wk old), preoperative day 3 and postoperative week 8. The m RNA expression of preproghrelin, GOAT and neuropeptide Y(NPY), and protein expression of ghrelin, GOAT, GHSR and the m TOR pathway(p-Akt, p-m TOR and p-S6) were measured in the hypothalamus.RESULTS SG can significantly improve metabolic symptoms by reducing body mass and food intake. The obese rats showed lower serum TG levels and no change in AG, but the ratio of AG/TG was increased. When compared with the S0 and Sh groups, the SG group showed decreased TG(1482.03 ± 26.55, 1481.49 ± 23.30 and 1206.63 ± 52.02 ng/L, respectively, P < 0.05), but unchanged AG(153.06 ± 13.74, 155.37 ± 19.30 and 144.44 ± 16.689 ng/L, respectively, P > 0.05). As a result, the ratio of AG/TG further increased in the SG group(0.103 ± 0.009, 0.105 ± 0.013 and 0.12 ± 0.016, respectively, P < 0.05). When compared with the S0 group, SG suppressed m RNA and protein levels of preproghrelin(0.63 ± 0.12 vs 0.5 ± 0.11, P < 0.05) and GOAT(0.96 ± 0.09 vs 0.87 ± 0.08, P < 0.05), but did not change NPY m RNA expression(0.61 ± 0.04 vs 0.65 ± 0.07, P > 0.05) in the hypothalamus. The protein levels of p-Akt, p-m TOR and p-S6 were higher in the SG group, which indicated that the hypothalamic m TOR pathway was activated after SG at the postoperative week 8. CONCLUSION The reduction of ghrelin expression and activation of the m TOR pathway might have opposite effects on food intake, as SG improves obesity and T2 DM.展开更多
Genome-wide and candidate gene association studies have identified several variants that predispose indi- viduals to developing nonalcoholic fatty liver disease （NAFLD）. However, the gene that has been consis- tentl...Genome-wide and candidate gene association studies have identified several variants that predispose indi- viduals to developing nonalcoholic fatty liver disease （NAFLD）. However, the gene that has been consis- tently involved in the genetic susceptibility of NAFLD in humans is patatin-like phospholipase domain contain- ing 3 （PNPLA3, also known as adiponutrin）. A nonsyn- onymous single nucleotide polymorphism in PNPLA3 （rs738409 C/G, a coding variant that encodes an amino acid substitution I148M） is significantly associated with fatty liver and histological disease severity, not only in adults but also in children. Nevertheless, how PNPLA3 influences the biology of fatty liver disease is still an open question. A recent article describes new aspects about PNPLA3 gene/protein function and suggests that the I148M variant promotes hepatic lipid synthesis due to a gain of function. We revise here the published data about the role of the I148M variant in lipogen- esis/lipolysis, and suggest putative areas of future research. For instance we explored in silico whether the rs738409 C or G alleles have the ability to modify miRNA binding sites and miRNA gene regulation, and we found that prediction of PNPLA3 target miRNAs shows two miRNAs potentially interacting in the 3＇ UTR region （hsa-miR-769-3p and hsa-miR-516a-3p）. In addition, interesting unanswered questions remain to be explored. For example, PNPLA3 lies between two CCCTC-binding factor-bound sites that could be tested for insulator activity, and an intronic histone 3 lysine 4 trimethylation peak predicts an enhancer element, cor- roborated by the DNase I hypersensitivity site peak. Finally, an interaction between PNPLA3 and glycerol- 3-phosphate acyltransferase 2 is suggested by data miming.展开更多
基金Supported by National Natural Science Foundation of China (30721063)National High Technology Research and Development Program of China (863 Program) (2006AA02A406)+1 种基金National Basic Research Program of China (973 Program) (2006CB503801)Special Fund of the National Laboratory of China (2060204)
文摘Objective To verify the regulation of acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT 2), which is associated with cholesterol metabolism, by saturated fatty acids (SFAs). Methods Palmitic acid (PA), the most abundant saturated fatty acid in plasma, and oleic acid (OA), a widely distributed unsaturated fatty acid, were used to treat hepatic cells HepG2, HuH7, and mouse primary hepatocytes. In addition, PA at different concentrations and PA treatment at different durations were applied in HepG2 cells. In in vivo experiment, three-month male C57/BL6 mice were fed with control diet and SFA diet containing hydrogenated coconut oil rich of SFAs. The mRNA level of ACAT2 in those hepatic cells and the mouse livers was detected with real-time polymerase chain reaction (PCR). Results In the three types of hepatic cells treated with PA, that SFA induced significant increase of ACAT2 expression (P<0.01), whereas treatment with OA showed no significant effect. That effect of PA was noticed gradually rising along with the increase of PA concentration and the extension of PA treatment duration (both P<0.05). SFA diet feeding in mice resulted in a short-term and transient increase of ACAT2 expression in vivo, with a peak level appearing in the mice fed with SFA diet for two days (P<0.05). Conclusion SFA may regulate ACAT2 expression in human and mouse hepatic cells and in mouse livers.
基金Supported by the National Natural Science Foundation of China,No.81270969(to Wei Zhang)and No.81300723(to Cheng-Xiang Shan)Shanghai Science and Technology Commission,No.12ZR1439100(to Wei Zhang)
文摘AIM To examine the changes of the ghrelin/ghrelin O-acyltransferase(GOAT) axis and the mammalian target of rapamycin(m TOR) pathway in the hypothalamus after sleeve gastrectomy.METHODS A total of 30 obese type-2 diabetes Sprague-Dawley(SD) rats, 6 wk of age, fed with high-sugar and highfat fodder for 2 mo plus intraperitoneal injection of streptozotocin were randomly divided into three groups: non-operation group(S0 group, n = 10), sham operation group(Sh group, n = 10) and sleeve gastrectomy group(SG group, n = 10). Data of body mass, food intake, oral glucose tolerance test(OGTT), acylated ghrelin(AG) and total ghrelin(TG) were collected and measured at the first day(when the rats were 6 wk old), preoperative day 3 and postoperative week 8. The m RNA expression of preproghrelin, GOAT and neuropeptide Y(NPY), and protein expression of ghrelin, GOAT, GHSR and the m TOR pathway(p-Akt, p-m TOR and p-S6) were measured in the hypothalamus.RESULTS SG can significantly improve metabolic symptoms by reducing body mass and food intake. The obese rats showed lower serum TG levels and no change in AG, but the ratio of AG/TG was increased. When compared with the S0 and Sh groups, the SG group showed decreased TG(1482.03 ± 26.55, 1481.49 ± 23.30 and 1206.63 ± 52.02 ng/L, respectively, P < 0.05), but unchanged AG(153.06 ± 13.74, 155.37 ± 19.30 and 144.44 ± 16.689 ng/L, respectively, P > 0.05). As a result, the ratio of AG/TG further increased in the SG group(0.103 ± 0.009, 0.105 ± 0.013 and 0.12 ± 0.016, respectively, P < 0.05). When compared with the S0 group, SG suppressed m RNA and protein levels of preproghrelin(0.63 ± 0.12 vs 0.5 ± 0.11, P < 0.05) and GOAT(0.96 ± 0.09 vs 0.87 ± 0.08, P < 0.05), but did not change NPY m RNA expression(0.61 ± 0.04 vs 0.65 ± 0.07, P > 0.05) in the hypothalamus. The protein levels of p-Akt, p-m TOR and p-S6 were higher in the SG group, which indicated that the hypothalamic m TOR pathway was activated after SG at the postoperative week 8. CONCLUSION The reduction of ghrelin expression and activation of the m TOR pathway might have opposite effects on food intake, as SG improves obesity and T2 DM.
基金Supported by Grants PICT 2008-1521 and PICT 2010 0441,from National Agency for Science and TechnologyUBACYT CM04,from Universidad de Buenos AiresSookoian S and Pirola CJ belong to National Council of Scientific and Technical Research
文摘Genome-wide and candidate gene association studies have identified several variants that predispose indi- viduals to developing nonalcoholic fatty liver disease （NAFLD）. However, the gene that has been consis- tently involved in the genetic susceptibility of NAFLD in humans is patatin-like phospholipase domain contain- ing 3 （PNPLA3, also known as adiponutrin）. A nonsyn- onymous single nucleotide polymorphism in PNPLA3 （rs738409 C/G, a coding variant that encodes an amino acid substitution I148M） is significantly associated with fatty liver and histological disease severity, not only in adults but also in children. Nevertheless, how PNPLA3 influences the biology of fatty liver disease is still an open question. A recent article describes new aspects about PNPLA3 gene/protein function and suggests that the I148M variant promotes hepatic lipid synthesis due to a gain of function. We revise here the published data about the role of the I148M variant in lipogen- esis/lipolysis, and suggest putative areas of future research. For instance we explored in silico whether the rs738409 C or G alleles have the ability to modify miRNA binding sites and miRNA gene regulation, and we found that prediction of PNPLA3 target miRNAs shows two miRNAs potentially interacting in the 3＇ UTR region （hsa-miR-769-3p and hsa-miR-516a-3p）. In addition, interesting unanswered questions remain to be explored. For example, PNPLA3 lies between two CCCTC-binding factor-bound sites that could be tested for insulator activity, and an intronic histone 3 lysine 4 trimethylation peak predicts an enhancer element, cor- roborated by the DNase I hypersensitivity site peak. Finally, an interaction between PNPLA3 and glycerol- 3-phosphate acyltransferase 2 is suggested by data miming.
